6500+ Quantitative Aptitude Questions and Answers With Explanation

Q:

A number is decreased by 10% and then increased by 10%. The number so obtained is 10 less than the original number. What was the oiginal number ?

A) 1000	B) 2000
C) 3000	D) 4000

Answer & Explanation Answer: A) 1000

Explanation:

Let the original number be x.

Final number obtained = 110% of (90% of x) =(110/100 * 90/100 * x) = (99/100)x.

x-(99/100)x=10

=> x =1000

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Filed Under: Percentage

142 51463

Q:

If the perimeter of a semicircle is 72 cm, then find its area (in cm²).

A) 308	B) 616
C) 160	D) 320

Answer & Explanation Answer: A) 308

Explanation:

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Filed Under: Area
Exam Prep: Bank Exams

0 51431

Q:

In how many different ways can the letters of the word 'OPTICAL' be arranged so that the vowels always come together?

A) 360	B) 700
C) 720	D) 120

Answer & Explanation Answer: C) 720

Explanation:

The word 'OPTICAL' contains 7 different letters.

When the vowels OIA are always together, they can be supposed to form one letter.

Then, we have to arrange the letters PTCL (OIA).

Now, 5 letters can be arranged in 5! = 120 ways.

The vowels (OIA) can be arranged among themselves in 3! = 6 ways.

Required number of ways = (120 x 6) = 720.

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Filed Under: Permutations and Combinations

51 51405

Q:

$Find the surface area (in {cm}^{2}) of a sphere of diameter 28 cm .$

A) 3422	B) 3852
C) 2464	D) 3550

Answer & Explanation Answer: C) 2464

Explanation:

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Filed Under: Volume and Surface Area
Exam Prep: Bank Exams

4 51319

Q:

50 men took a dip in a water tank 40 m long and 20 m broad on a religious day. If the average displacement of water by a man is 4 cu.m , then the rise in the water level in the tank will be:

A) 20 cm	B) 25 cm
C) 35 cm	D) 50 cm

Answer & Explanation Answer: B) 25 cm

Explanation:

Total volume of water displaced =(4 x 50) cu.m = 200 cu.m

Rise in water level = $(\frac{200}{40 \times 20})$ =0.25m = 25cm

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Filed Under: Volume and Surface Area

64 51168

Q:

The G.C.D of 1.08, 0.36 and 0.9 is

A) 0.03	B) 0.9
C) 0.18	D) 0.108

Answer & Explanation Answer: C) 0.18

Explanation:

Given numbers are 1.08 , 0.36 and 0.90

H.C.F of 108, 36 and 90 is 18 [ $∵$ G.C.D is nothing but H.C.F]

Therefore, H.C.F of given numbers = 0.18

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Filed Under: HCF and LCM

138 51066

Q:

If 20 men can build a wall 56 meters long in 6 days , what length of a similar wall can be built by 35 men in 3 days?

A) 46	B) 47
C) 48	D) 49

Answer & Explanation Answer: D) 49

Explanation:

Let the required length be x meters

More men, More length built (Direct proportion)

Less days, Less length built (Direct Proportion)

$\begin{array}{r} \begin{matrix} M e n & 20 : 35 \end{matrix} \\ \begin{matrix} D a y s & 6 : 3 \end{matrix} \end{array}\} ⋮ ⋮ 56 : x$

=> (20 x 6 x X)=(35 x 3 x 56)

=> x = 49

Hence, the required length is 49 m.

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Filed Under: Chain Rule

156 51046

Q:

Reena took a loan of Rs. 1200 with simple interest for as many years as the rate of interest. If she paid Rs. 432 as interest at the end of the loan period, what was the rate of interest?

A) 3.6	B) 6
C) 18	D) Cannot be determined

Answer & Explanation Answer: B) 6

Explanation:

Explanation:

Let rate = R% and time = R years.

Then, $(\frac{1200 * R * R}{100}) = 432$

$12 R^{2} = 432$

=> $R^{2} = 36 \Leftrightarrow R = 6$

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Filed Under: Compound Interest

118 51044

Quantitative Aptitude - Arithmetic Ability Questions

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